Caption: Virtual reality in physics. Computer-generated image showing part of the proposed Large Hadron Collider (LHC), a particle accelerator to be built at the CERN European particle physics laboratory. The LHC pipe is shown in blue, and will be built above the existing Large Electron-Positron (LEP) accelerator (grey and yellow). A figure (red) is shown for scale. LEP occupies a ring- shaped tunnel some 27 kilometres in circumference. This frame was made using CERN's VENUS virtual reality system. It is used to check engineering designs for fit and position before any component is actually manufactured; this process is called virtual prototyping.